function Person() { 
  // say: function() {
  //   console.log('hello');
  // }

  this.name = 'xiaoming'

  this.say = function() {
    console.log('hello:' + this.name);
  }
}

Person.prototype.walk = function() {
  console.log('walking...');
}

let p1 = new Person()

// console.log(p1.say());

p1.walk()



